Level indicator for fork type lift trucks



Aug. 14, 1962 A. E. BERTENSHAW ETAL 3,049,257

LEVEL INDICATOR FOR FORK TYPE LIFT TRUCKS Filed Nov. 23, 1959 AL E 15%;synw A270 EA/EV United States Patent n spams? LEvnL INDICATOR non FonKrvrn LIFT TRUCKS Allen E. Bertenshaw, Markham, and Francis .1. Bazata,Chicago, 111., assignors to international Harvester Company, Chicago,111., a corporation of New Jersey Filed Nov. 23, 1959, Ser. No. 854,6891 Claim. (Cl. 214-674) This invention relates to an indicating device.More specifically the invention relates to a device used on a fork typelift truck which is adapted to indicate the position of the horizontalforks to an operator.

The present invention has to do with a lift truck generally utilized inmaterial handling and particularly adapted for moving articles. Such atruck is shown in the Repke Patent 2,456,320, patented December 14,1948. In a lift truck of this type a vertical lifting frame is pivotallymounted on the forward end of a wheeled tractor or truck. The liftingframe supports a fork type lifting platform which is vertically movableon the vertical frame for raising and lowering pallets and the like.Generally the lifting platform is raised by means of hydraulic rams andthe vertical frame may be tilted from the vertical slightly forwardly orrearwardly by means of another suitable hydraulic ram. The tiltingmovement of the vertical frame results in the tilting of the horizontalplatform from the horizontal to a downwardly or upwardly inclinedposition. The tilting arrangement is desirable to facilitate the entryof the fork platform underneath objects to be lifted or into therecesses of suitable pallets. For instance the lifting platform may beinclined downwardly while the truck is moving in a forward direction andthus an object seated upon floor may be engaged whereupon the fork maythen be tilted upwardly to retain the object on the fork while it israised to the desired position. In order to expedite material handlingwith this type of truck it is extremely desirable that the operator, atany given time, knows the position of the platform with regard to thehorizontal or an inclined position. Also the degrees of inclination areextremely important. Thus it is a prime object of the invention toprovide an improved indicating device which is readily visible from theoperators station and which will promptly indicate the position of alifting type platform.

Another object is the provision of a simplified indicator particularlyadapted for lift type trucks, the said indicator including a minimum ofparts and being adapted to provide visual indicating means to anoperator to indicate the tilted position of a lifting platform.

A still further object is to provide an indicator for lift type trucks,the said indicator including a pair of relatively movable indicatingelements hingedly connected to a vertical frame of the lifting platformand to the body of the truck, the said elements being movablesimultaneously with the vertical lifting frame to indicate the positionof a lifting platform.

These and other objects will become more readily apparent from a readingof the specification when examined in connection with the accompanyingsheet of drawing.

In the drawing:

FIGURE 1 is a side elevational view of the forward portion of a forktype lift truck having an improved indicating means positioned thereonand showing a lifting platform in position adjacent a palletized object;

FIGURE 2 is an enlarged side elevational view, partially in section,showing an indicating device for lift trucks; and

FIGURE 3 is a plan View, of reduced scale of the indicating device shownin FIGURE 2.

l,25? Patented Aug. 14, 1952 Referring now particularly to FIGURE 1, afork type lift truck is generally designated by the reference character10. The truck 10 comprises a body 11 suitably supported on ground wheels12. Only the forward portion of the truck is shown and it is generallyconventional in detail, as shown for instance in the aforementionedpatent. The body 11 is provided with an operators station 13 and thewheels 12 are steered by a suitable steering wheel 14. A supportingplatform 15 is mounted on the forward end of the body 11. The supportingplatform 15 supports a vertical lifting frame 16 by means of a suitablehinge 17.

A lifting platform is generally designated at 18, the said platform 18comprising a pair of horizontally extending laterally spaced forks 19suitably connected to vertical supports 31 which in turn are connectedto a raising and lowering means (not shown) positioned within thelifting frame 16. A fluid cylinder is indicated at 21. The fluidcylinder 21 is pivotally supported on the body by means of a pivot 22and includes suitable fluid conduits 23 which alternately supply fluidunder pressure to opposite ends of the cylinder 21 for reciprocating aram or piston rod 24 which is pivotally connected to the lifting frame16 as indicated at 25. I

An indicating device, best shown in FIGURES 2 and 3, is designated bythe reference character 26. The indicating device 26 comprises a pair ofspaced brackets 27 suitably connected to the body of the vehicle 11 asshown in FIGURE 1. A first indicating member 28, in the form of a roundor rectangular tube, is hingedly connected to the bracket 27 by means ofa transversely extending hinge pin 29 as shown in FIGURE 3. Theindicating member 28 is provided with inner walls 30, the top inner wall30 being suitably cut out to provide a slot 31 as best shown in FIGURE3. The slot 31, by virtue of the position of the indicating device 26,as shown in FIGURE 1, is readily within sight or view of the operator onthe operators station 13. A pair of indicating means or blocks 32 aresuitably connected to the member 28 in transversely aligned relation asshown in FIGURE 3. A second indicating member is designated at 33, thesaid member 33 being slidably or telescopingly positioned within thefirst indicating member 28. The second indicating member 33 is providedat one end with an opening 34 through which a hinge pin 35 is placed,the said hinge pin 35 being suitably secured to the vertical frame 16 sothat the second indicating member 33 is hingedly connected thereto. Theindicating member 33 also includes a transversely extending bar orsuitable indicia marking 36 which is adapted to be transversely alignedwith the blocks 32 in a certain position of the member 33 relative tothe member 28.

In FIGURE 1 the truck 10 is shown in position relative to a pallet 37 ofconventional construction. In operation the forks 19 of the liftingplatform 18 may be moved into engagement with the pallet 37, which isprovided with the usual recess (not shown) within which the forks 19 maybe placed. In the entry into the pallet 37 the forks 19 are positionedin a horizontal position and upon engagement it may be desirable toincline the lifting frame 16 rearwardly to the broken line positionshown in FIGURE 1 to assure that the pallet 37 is positively placed onthe lifting platform 18. To achieve this inclination rearwardly thefluid device 21 is actuated so that the ram 24 moves rearwardly.Conversely, if it is desired to incline the forks from the horizontaldownwardly the frame 16 is moved to a forward position as shown in thebroken line arrangement of FIGURE 1. Besides lifting of palletizedobjects there are many instances where inclination of the forks isdesired depending upon the material handling operation to be performed.Thus it is highly desirable that the operator very quickly andpositively knows the exact position of the fork. Thus the indicatingdevice 26- eflectively discloses the position of the forks 19. Forinstance if the lifting platform 16 is moved forwardly the indicator 36is moved to the position shown in FIGURE 3 at A. If the lifting frame 16is moved rearwardly, the indicator may be moved to the position shown inFIGURE 3 at B. In the level position the indicator 36 is in transversealignment with the blocks 32. Thus the operator knows the exact positionof the forks with respect to the horizontal or upwardly or downwardlyinclined positions. It is, of course, readily apparent that additionalindicating means similar to 32 may be employed on the member 28 toindicate the inches or degrees of tilting as desired. Thus by simplyglancing at the indicator the operator at all times known the positionof the forks 19. This greatly facilitates the material handlingoperations since it is often diflicult to know exactly the position ofthe forks 19.

Thus it is believed that the objects of the invention have been clearlyachieved and it must be understood that changes and modifications may bemade without departing from the spirit of the invention as disclosed orfrom the scope thereof :as defined in the appended claim.

What is claimed is:

A position indicating device for a lift truck having a body, a verticallifting frame connected to said body, a vertically movable normallyhorizontal lifting platform connected to said lifting frame, and fluidextensible means connected to said body and said vertical frame fortilting said frame forwardly and rearwardly of said body whereby saidplatform is tilted from a horizontal position to an upwardly inclined ordownwardly inclined position; comprising a bracket connected to saidbody, a tubular member hingedly connected to said bracket, said tubularmember having an elongated slot disposed in a position within sight ofan operator on said truck, an indicating member disposed within saidtubular member in relative sliding relation, said indicating memberhaving a first indicating means thereon visible through said slot, asecond indicating means on said tubular member disposed adjacent saidslot, and means hingedly connecting said indicating member to saidvertical frame whereby on tilting of said frame said first indicatingmeans is moved relative to said second indicating means to a positiondenoting a horizontal or tilted position of said platform.

References Cited in the file of this patent UNITED STATES PATENTS

